Grafting is the most common method of queen rearing and is used worldwide. To the best of my knowledge it is used by most of the commercial queen breeders, presumably because it is quick, cheap and reliable.
Grafting is simply the transfer of larvae that were intended to be workers into queen cell cups. In my view it should be termed “Larval Transfer” because that is a more accurate description, but I will continue to refer to it as grafting to avoid changing terminology.
Grafting is known universally as the “Doolittle” method, but Michael Bush has researched queen rearing methods and found that others had been using similar methods for some considerable time before Doolittle.
Worker larvae are transferred from cells in comb into queen cell cups, then placed in a colony that is in the right condition to convert them into queen cells. It’s that simple! And simultaneously very complicated.
Grafting is a good method for those who want a reasonable number of Q/Cs because it is easy to control. You decide which larvae to use and within reason they are all the same age. Once set up it is quick and any rejects can be regrafted easily. Many “Queen Rearing” lectures and demonstrations concentrate on grafting, but I think it is not worth the small scale beekeeper learning how to do it, when there are easier methods that may suit them better. I have never used this method successfully. As it is the method that is pushed by everyone, they think it is the only way to rear queens and give up. What a pity?
Size and Age of Larvae
Worker and queen larvae receive the same food for the first 48 hours, i.e. 5 days from the laying of the egg. The ageing of larvae is an important part of beekeeping and should be taught by Beekeeping associations. This is easy to do yourself by checking daily after a queen has started to lay. Larvae that are too old will not receive the full amount of food and will make poor queens, so knowing the age is very important.
I prefer to use the smallest larvae I can easily handle and to try to use those of the same size, so aim at 24-36 hours old. This ensures they all emerge at roughly the same time. I think it is a mistake to attempt to use larvae that are too small, because they are very delicate and easily damaged. In my experience the smaller they are the more casualties there are and that may be the reason why.
Wet or Dry?
Some graft “wet” which is where royal jelly that is harvested from existing Q/Cs is diluted with distilled water and placed in the cell cups. It is claimed it is easier to float the transferred larvae into the cell, prevents drying out, gives the larvae a good start and increases acceptance. I have tried both “wet” and “dry” grafting on enough occasions to say that I haven’t seen any obvious difference, neither has worked for me, so I now cell punch. You please yourself, because that’s what you will be happiest with.
It is sometimes advised, especially in older books, to graft in the normal way, then after a day remove the larvae and graft again with fresh larvae onto a large bed of royal jelly. The idea is that this causes the second batch of larvae to be better fed than the first lot. It has now been shown this may not be a good thing to do, because the royal jelly changes as the larvae gets older.
Many of the books will tell you to perform grafting in a room with a constantly boiling kettle to keep the atmosphere humid. This may be desirable, but not always necessary. Like Dave Cushman did, I do most of my cell punching out of doors or in the front seat of my truck. I use a hive roof on a colony that is a comfortable height and that is it. I don’t bother about hot water bottles, towels or any of the other aids that have been suggested. Temperature isn’t too important, as I have grafted on days when it has been rather cool. What is important is the larvae shouldn’t dry out and that can be caused by direct sunlight or wind.
What to graft into.
There are a number of types of cell cups a variety are discussed below.
Dipped wax cups formed around a wetted wooden dowel. In the past some systems have had multiple dipping ‘combs’ of forming sticks set at the same spacing as the cups are required, so that the cups are first dipped then attached to the bar, with molten wax, before the former is withdrawn, thus a finished cell bar is produced in one operation. I suspect this needed a high degree of skill and may not have been used much.
The forming stick is best made of beech as it is hardwood and stands up to the constant wetting and retains a degree of polish. Start with a 9 mm (or 3/8″) blank, whittle it round and slightly tapered so that a hemispherical end can be fashioned that is 8 mm (5/16″) in diameter. Then polish smooth with 600 grit ‘wet and dry’ abrasive paper. Place the stick in the chuck of a battery powered drill and wrap the abrasive paper around it with a gloved hand (it will get hot!).
Moulded wax cups have come into use as several can be made at the same time. The moulds are usually made from silicone rubber and usually have multiple impressions. There is a further type that is a combination of the two methods whereby the ‘mould’ is in the form of ten silicone rubber fingers, the tips of which are dipped into molten wax.
Wax cups are now rarely used and only by small scale queen rearers. They are time consuming to make and have to be fixed to a bar in some way, usually with molten wax. Plastic cell cups are cheap and easy to use. The Jz-Bz type is the most commonly used and are made in six colours which helps identify which colony the larvae came from.
JzBz Cell Cup colored Plastic Cell Cup
The yellow type is available in and fits into a grooved aluminium rail that is in turn mounted on the underside of the cell bar. This type benefits from a small flat cut on the end of one of the curved lugs which allows it to ‘snap’ in place into the rail and gives a more secure fit. The cups can also be fitted onto tapered wooden dowels.
My Thoughts on Grafting.
I prefer to use the Chinese Grafting Tool, rather than one of the many other options. They are poorly made and easily break or fall to bits, so I make sure I have several of them. I like the JzBz plastic cell cups that are referred to as the “Wide Base Cell Cup” type. These are the most popular and have an oval spigot on the back, which is intended to be put in a wooden bar with a slot in and twisted until it holds. I don’t use that method, but drill 10 holes in a softwood bar and nail that in a brood frame, so it twists for ease of use. The cell cups are simply pushed in the holes.
My cell bars are identified and I have 10 stations, each numbered which helps with recording. In conjunction with the colours of the JzBz cups I am able to graft larvae from more than one colony on a bar, so I know where G8 or E3 came from.
If I wish to have virgin queens emerge before I am able to do anything with them I graft into Cupkit cells and holders so I can cover the cells with rollers to imprison the emerged queens. I also do this if I wish to cull emerging virgins on colour, or to check they have fully formed wings.
Plastic cell cups can be cleaned if you wish. I don’t always bother, apart from removing the worst with an lollipop stick that has been shaped. It doesn’t seem to matter.
I check a couple of hours after placing the grafts in the cell building colony. Most rejects will be removed within this time. If I have time I regraft then, otherwise I wait until the next day.